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LT1129 - Micropower Low Dropout Regulators with Shutdown

The LT1129/LT1129-3.3/LT1129-5 are micropower low dropout regulators with shutdown. The devices are capable of supplying 700mA of output current with a dropout voltage of 400mV at maximum output. Designed for use in battery-powered systems, the low quiescent current, 50μA operating and 16μA in shutdown, make them an ideal choice. The quiescent current does not rise in dropout as it does with many other low dropout PNP regulators. Other features of the LT1129 /LT1129-3.3/LT1129-5 include the ability to operate with small output capacitors. They are stable with only 3.3μF on the output while most older devices require between 10μF and 100μF for stability. Also the input may be connected to ground or a reverse voltage without reverse current flow from output to input. This makes the LT1129/LT1129-3.3/LT1129-5 ideal for backup power situations where the output is held high and the input is at ground or reversed. Under these conditions, only 16μA will flow from the output pin to ground. The devices are available in 5-lead TO-220, 5-lead DD-Pak and 3-lead SOT-223 packages.

Features 400mV Dropout Voltage 700mA Output Current 50μA Quiescent Current No Protection Diodes Needed Adjustable Output from 3.8V to 30V 3.3V and 5V Fixed Output Voltages Controlled Quiescent Current in Dropout Shutdown 16μA Quiescent Current in Shutdown Stable with 3.3μF Output Capacitor Reverse Battery Protection No Reverse Output Current Thermal Limiting Surface Mount SOT-223 and DD-Pak Packages Typical Application

Applications Low Current Regulator Regulator for Battery-Powered Systems Post Regulator for Switching Supplies 5V to 3.3V Logic Regulator Packaging